Register two or more emails for MFA

I have single admin user, when I want to login, the MFA goes to a admin account email which is sometime unavailable, so how can I add another email for the same admin user that the MFA goes to.

The issue was resolved, the problem was that I misunderstood MFA and Notification settings, Notification emails can be multiple but the MFA will only come on a single email which the email which was used to create the admin account. I solved it by creating an another admin user for the site, This solution is for anyone who is having a similar problem.